The human metagenome: our other genome?

Abstract

For about a decade, the human microbiota has been investigated using molecular procedures that are now systematized via metagenomics. Several large scale studies are underway with the goal of establishing a set of reference data, such as catalogues of genes, microbial species and complete genome sequences of strains colonizing the various body sites. A first series of conclusions can be drawn from this ‘natural history’ approach that will also lay the ground for further studies aiming at understanding—in an ecological perspective—the mechanisms ensuring stable operation of the microbiota in healthy individuals, and how changes in its composition (dysbiosis) may result in diseases.